Pressure-operated feeding apparatus for combustion liquids in an internal combustionchamber



June 12, 1956 R. H GODDARD 2,749,884

PRESSURE-OPERATED FEEDING APPARATUS FOR COMBUSTION LIQUIDS IN ANINTERNAL COMBUSTION CHAMBER Filed Dec. 11, 1952 2 Sheets-Sheet 1 IN V ENTOR ROBERT H. GODDARD, DECD. ESTHER c. GODDARD,EXEGUTRI June 12, 1956 R.H. GnDDARD 2,749,884

PRESSURE-OPERATED FEEDINL .PPARATUS FOR COMBUSTION LIQUIDS IN ANINTERNAL COMBUSTION CHAMBER Filed Dec. 11, 1952 2 Sheets-Sheet 2 r U 80M 76 33 j; 11 73 as D IL I I M l P a"/ x i I r I 1%! E 70 T3 INVENTOR.

t ROBERT H. GODDARD DEcD.

ATTY.

ESTHER c. GODDARD, ExcuTmx.

Unite States harem PRESSURE-OPERATED FEEDING APPARATUS FOR COMBUSTIGNLE-QUTDS IN AN INTER- NAL CGMEEUSTKUN Application December 11, 1952,Serial No. 325,255

1 Claim. (U. Hi -43) This invention relates to internal combusionchambers as used in rockets and other propulsion apparatus. It is commonpractice to operate such combustion chambers by using a liquid fuel, asgasoline, and a liquid oxidizer, as liquid oxygen. Each of thesecombustion liquids must be fed to the combustion chamber uniformly andcontinuously.

It is the general object of this invention to provide improved andsimplified apparatus for thus continuously feeding the two combustionliquids.

In the preferred embodiment of the invention, the liquids are fed. tothe combustion chamber by two separate centrifugal pumps which areoperated by a single gas-driven turbine. Liquid nitrogen from arelatively low pressure storage tank is pumped through a heating coilsurrounding the combustion chamber and is thereby vaporized. Thisnitrogen gas, vaporized at much increased pressure, then actuates theturbine which drives the two centrifugal pumps.

The nitrogen pump is preferably of the reciprocating type and isoperated by a pneumatic motor which is supplied with compressed air ornitrogen gas through a solenoid-operated valve. The power circuit forthe valve solenoid has a control switch which is associated with thepneumatic motor in such manner that the switch is closed at the end ofeach upward or pumping stroke and is opened at the end of each downwardor return stroke.

The invention further relates to arrangements and combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claim.

A preferred form of the invention is shown in the drawings, in which-Fig. 1 is a diagrammatic front elevation showing the associated parts ofthe entire system, but with the several parts drawn to different scales;

Fig. 2 is a detail side elevation, looking in the direction of the arrow2 in Fig. 1;

Fig. 3 is an enlarged sectional front elevation of the pneumatic motor;

Fig. 4 is an enlarged sectional front elevation of the nitrogen pump;

Figs. 5 and 6 are enlarged sectional views of certain valves shown inFig. 4; and

Figs. 7 and 8 are perspective views of the valves shown in Figs. 5 and 6respectively.

Referring to Fig. 1, a combustion chamber C of conventional type isshown as provided with the usual open rearward discharge nozzle N.

The chamber C is supplied with liquid oxygen from a storage tank T by acentrifugal pump P, and is supplied with gasoline or other liquid fuelfrom a tank T2 by a pump P2. The impellers of the pumps P and P2 aremounted on a common shaft 10 which also supports the rotor of agas-driven turbine R.

Liquid nitrogen is stored under relatively low pressure in a tank T3,and is delivered by a reciprocating pump P3 to a heating coil 12 woundabout the combustion ice chamber C. The lower end of the heating coil isconnected by a pipe 14 to a nozzle 15, and the vaporized nitrogendelivered under substantial pressure through the nozzle 15 operates theturbine R to drive the pumps P and P2.

The nitrogen pump P3 is operated by a pneumatic motor M, which motor issupplied with compressed air or nitrogen gas through a pipe 29 whichconnects the motor M to a valve V which has a supply pipe 22 and anexhaust connection 23. A branch pipe 24 connects the pipes 14 and 22,and usual shut-off valves permit operation with either air or nitrogengas.

The valve V is shown as of the piston type, and with the piston rod 25connected to a plunger 26 which extends into a solenoid coil 36. Thecoil 30 is connected direct to aline wire L and is connected to a secondline wire L2 through a switch S.

The switch S is connected to the upper end portion 33a of an axiallymovable rod 33 (Fig. 3) in the motor M. The switch is closed as the rod33 reaches the upper end of its working stroke and is opened at thelower end of the return stroke.

From this condensed description, the general operation will be apparent.When the main switch S2 is manually closed and the control switch S isalso closed, the valve V will be positioned to connect the supply pipe22 through the connecting pipe 20 to the motor M, thus producing adownward or return stroke of the pump P3 and permitting liquid nitrogento flow into the pump P3 from the tank T3 which is under limitedpressure.

At the end of the downward or return stroke, the switch S is opened, thevalve V is reversed, the motor M is connected to exhaust, the movingparts of the pump P move upward on a working stroke, and liquid nitrogenis pumped into the heating coil 12 and thence as nitrogen gas atsubstantially higher pressure to the turbine T. p

The details of construction of the pump P3, the motor M and certainassociated parts are shown on Sheet 2 of the drawings and will now bedescribed.

The pump P3 comprises a bottom plate 43 secured to the upper face of anannular member 41 mounted in an inner frame 44 slidable in a fixed outerframe F. A recessed casing member 42 is secured to the annular member 41and has a flexible connection 43 to a feed pipe 43a extending nearly tothe bottom of the tank T3.

A frame member 45 forms part of the fixed frame F and is provided withan inwardly-extending flange 46 and with guide passages 47 for thetubular side members 48 of the movable frame 44. A relatively deep shellor bushing 50 is secured to the flange 46 and extends downward therefromand has a fixed bottom portion 51 which supports an upwardly-openingcheck valve V3. A bellows member 55 is connected at its lower end to themovable plate 49 and at its upper end to the fixed flange 46 and bushing50.

A cone-shaped member 57 is mounted within the fixed shell or bushing 50and has an upwardly-extending sleeve portion 58 secured to said bushing50. At its upper and inner end, the cone-shaped member 57 is connectedto a delivery pipe 60, which in turn is connected to the heating coil 12(Fig. 1) previously described. A suitable check valve V4 may be providedin this connection.

The inner and movable frame 44 is secured to the lower end of thereciprocating rod 33 previously described, and this rod is alternatelymoved upward for a pumping stroke and downward for a return stroke.

On the downward return stroke, the valve V2 opens and liquid nitrogenwill flow under the tank pressure through the valve V2 and into thespace above the plate 40. The valve V3 is held closed by the pressure inthe pipe 60 and coil 12.

On the following upward or working stroke, the rod 33 and frame 44 willmove upward (the valve V2 being now closed), and the liquid nitrogenbetween the movable bottom plate 40 and the fixed bottom plate 51 willbe forced out through the check valve V3 to the delivery pipe 60 andthence to the heating coil 12.

Successive portions of liquid nitrogen are thus pumped to the heatingcoil 12 on the upward or working strokes of the pump P. A pressure andstorage tank T4 may be inserted as indicated in Fig. 1 to provide moreuniform pressure in the coil 12.

The pneumatic motor M shown in section in Fig. 3 comprises an outercasing 70 having upper and lower end members 71 and 72. The lower endmember 72 is connected to a sleeve 73 which is secured to the upper endof the fixed frame F (Fig. 4) of the pump P3. A by-pass 74 connects theinterior of the member 72 to the tank T3 and has the usual shut-citvalve. The interior of the member 72 is connected through restrictedopenings as shown to the interior of the casing 70.

An axial tube '75 is fixed in the upper casing member 71 and extendsdownward a substantial distance within the casing 70. At its upper end,the tube 75 is connected by a ring or disc 76 to an inner tube 80, whichtube extends substantially downward within the casing 70 and tube 75.The lower ends of the tubes 75 and 80 have a disc 81 connecting thebottom ends thereof. A bellows member 83 is connected at its upper endto the casing end member 71 and at its lower end to a disc 85 mounted onthe rod 33. The bellows 83 may preferably be formed in two partsconnected by a sliding ring 87.

A compression spring 88 is positioned between the axial rod 33 and theinner tube 80, and at its lower end rests on the bottom plate 85. At itsupper end, the spring engages a vented cap 90 within which the rod 33 isslidable. -The supply pipe 20 previously described is connected into theupper end of the inner tube 81).

During a working stroke, the pipe 20 is connected to exhaust, andpressure from the nitrogen tank T3 pushes the bottom plate 85 and rod 33upward and at the same time further compresses the spring 88. Thisfeeding movement is relatively slow, as it is eifected only by the flowof liquid nitrogen through the restricted openings in the lower endmember 72. This relatively slow feeding movement is essential to provideenough time for vaporization of the liquid nitrogen in the coil 12 (Fig.1). At the upper end of the stroke, the switch S is closed, pressure isadmitted through the connection 20, and the combined action of the airpressure against the plate 85 and the force of the spring 88 on theplate 85 forces the plate 85 and rod 33 downward for a return stroke ata relatively much higher speed. This higher return speed permits thepumping action to be substantially continuous.

At the end of this return stroke, the switch S is opened, the pipe 20 isconnected to exhaust, and the cyle is repeated.

In order to provide a delayed action of the switch S, the switch S has apin-and-slot coupling connection 92 (Fig. 2) with the rod 33a, so thatmovement of the switch S takes place only at the extreme opposite endsof the movements of the rod '33. The switch S has suitable frictionalcontact which retains it in either open or closed position untildefinitely moved therefrom.

The details of construction of the valves V2 and V3 are clearly shown inFigs. 5 to 8. Each valve comprises a relatively thin flexible seatingmember, as 95 or 96, which members are enclosed between stiffeningplates 97-97a. Excessive displacement of the valve V3 is prevented by anover-hanging fixed ring 99, and similar displacement of the valve V2 isprevented by lower cross bars 100.

Having thus described the invention and the advantages thereof, it willbe understood that the invention is not to be limited to the detailsherein described, otherwise than as set forth in the claim, but what isclaimed is:

A fluid-operated motor comprising a closed casing, a bellows membertherein, restricted means to supply liquid under relatively low pressureto the space within said casing and exterior to said bellows member, andthe lower end of said bellows member closing off said liquid supply whendepressed, means to supply a gaseous fluid under relatively highpressure to the interior of said bellows member, a compression spring insaid bellows memher acting in opposition to the liquid pressure and inconjunction with the gaseous fluid pressure, a valve shiftable toalternately connect the interior of the bellows member to said gaseousfluid supply or to exhaust, and a device to shift said valve which isactivated by said bellows member at the upper end of the working strokeof the motor, said working stroke being effected at relatively low andcontrolled speed entirely by restricted flow of liquid at relatively lowpressure, and the idle or return stroke of said motor being effected atrelatively high speed by conjoint gaseous and spring pressure whichovercomes the liquid pressure and closes off the liquid supply.

References Cited in the file of this patent UNITED STATES PATENTS348,361 Van Order Aug. 31, 1886 542,543 Thomas July 9, 1895 706,688Reynders et al Aug. 12, 1902 1,200,826 Forman Oct. 10, 1916 1,408,208Jones Feb. 28, 1922 1,734,368 Cumner Nov. 5, 1929 1,959,889 Wunsch May22, 1934 2,281,675 Condit May 5, 1942 2,395,113 Goddard Feb. 19, 19462,419,993 Green et al. May 6, 1947 2,585,626 Chilton Feb. 12, 1952

